Got some steppers.. any ideas about controllers

[millberg]

I just picked up three steppers for 100 bucks. This is what is on them:
Superior Electric
Slo-sync
1.8 deg/step
1.5 V
11.0 Amps
300 oz. inch


Any ideas about a controller?

[ger21]

Those are not very desirable motors, due to the high current rating. Geckos only handle 7 amps, which would only give you about 2/3 of the rared torque. And if you're only going to get 200oz of torque, you could get a Xylotex or HobbyCNC driver AND 200-250oz motors for probably less than the price of the geckos.

[buscht]

The main thing I noticed on these steppers is the 11.0 amps. That rules out some of the less expensive boards like the HobbyCNC board or the Xylotex.

Maybe the FET3 from Stepperworld? http://www.stepperworld.com/
Are the stepper motors bipolar or unipolar?

Otherwise, you should use a Gecko or Rutex drive.

[millberg]

I have no spec. sheets for them and haven't been able to find them at the Superior site. They have 6 wires coming out. I should be able to run them unipolar or bipolar depending on how they are wired. I do electronics for a living so I might have to build something.

[millberg]

Thanks for the link to stepper world. It looks like they have just what I need. They have a controller that will handle 14 amps for $135. Nice. Now I just need to get me a power supply that will put out 66+ amps. Sounds like a welder to me. Ha. Thanks again.

[jeffs555]

If they have 6 wires, then they are designed for unipolar drive, and the 11 amps is probably the unipolar rating. If you drive them bipolar using the outside wires and leaving the center taps unconnected, you will get the same torque using half the current. Driving them bipolar using all the coils like that, you can usually run them at .707 times the unipolar current and get increased torque.

[Evodyne]

Jeffs555 beat me to the punch. You can run the motors with a bipolar drive and use only the outer taps of the center-tapped coils. Total winding resistance is then double the unipolar rating, which is measured from the center tap to the end of the winding.

Double the resistance and you halve the current, so you would peak out at 5.5 amps. Now you could run a Geckodrive wide open-they are good for seven amps. You would absolutely need a heatsink though.

I meantion the Geckos because they are what I have experience with. I might be biased, but I really like them.

I found it cheaper to build independant supplies-one per drive-than to build a "welding machine".

[jeffs555]

Also, it looks like the stepperworld drives are not chopper type drives and require series resistors. A chopper drive with microstepping like the Gecko would be much better, and work with a smaller power supply. There is a white paper on the Gecko site that says they only need a supply rated at 2/3 of the current setting. With the Geckos driving the full coils in bipolar, you could probably get by with a 15 to 20 amp supply of 24 to 48 volts.